The rehabilitation of a patient with Acquired Brain Injury begins during the acute treatment phase. It is important to focus on maximizing the patient's capabilities at home and in the community. Positive reinforcement helps recovery by improving self-esteem and promoting independence. In this context, user interface design is very important for several reasons. First of all the more intuitive the user interface the easier it is to use. The better the user interface is the easier it is to train people to use it, reducing training costs. The better your user interface is the more your users will like to use it, increasing their satisfaction with their work. In this paper a web-based system, namely HABITAT, for the treatment of Acquired Brain Injured is presented, which has been design by means of model-based user interface design techniques to maximize the effectiveness of the treatment activities.